This invention relates to chemical spraying units, and more particularly, to horticultural chemical spraying units for mixing water and a chemical such as a fertilizer, insecticide, or the like, for horticultural uses.
More particularly, the present invention contemplates the provision of a pressure controlled automatic bypass system in connection with water and chemical supply units which is responsive to the pressure generated by opening and closing of the discharge nozzle for selectively bypassing water and chemicals from an input to the discharge nozzle to the respective supply tanks. In addition, means are provided for automatic metering of the chemical output and for providing indications of the occurrence of flow as well as the volumetric flow.
Prior art devices for mixing liquid and chemicals typically include mechanically interconnected linkages and systems which are not easily adjustable nor particularly reliable in operation. In the present invention, a hydraulically controlled bypass valve eliminates the problems created with mechanical devices and produces a quicker response time and function. It also prevents any intermixing of liquids, provides full control of both liquids and has a fail-safe feature described herein.
The present system is designed for use by professional landscape horticulturists in applying treatments of varied nature to plants. These treatments are commonly water dispersions of insecticides or fungicides sprayed on the foliage of trees, shrubs, and lawns; and dissolved fertilizer materials in water which are injected into the soil or sprayed on a lawn.
The needs of plants are somewhat diverse so that several different mixtures are sometimes needed in a normal day's work. Commercial sprayers now available for these purposes fail to meet the landscape horticulturists' need in several respects.
In the present system, two pumps, respectively for chemicals and water, are positive displacement, piston types and are chain driven together by a governor controlled gasoline engine. The chain drive ratio between pumps is calculated to produce an output ratio of one part chemical material to four parts water by volume. The chemical mixes in the multiple tanks contain the ratio necessary to mix 4 parts of water to 1 part of chemical.